Residential air conditioning systems utilizing the absorption refrigeration cycle to alternately accomplish either cooling or heating are generally well known. One example of such a system is the gas-fired, Arkla-Sun Valley absorption machine employing a lithium bromide/water refrigerant solution in a single effect absorption refrigeration cycle with a direct expansion evaporator and atmospheric rejection of absorber heat through a separate hydronic loop. Also, utilization of a double effect absorption refrigeration cycle in applications requiring alternate air cooling and heating is well known as taught by U.S. Pat. No. 4,441,332 issued in the name of William H. Wilkinson.
However, such known air conditioning systems as applied to typical residential cooling and heating applications have not achieved optimum energy conversion efficiencies, have proven costly to implement and operate, and have operational drawbacks such as tendency toward salt crystallization and reduced ability to recover from salt recrystallization in the case of sustained power outage.
I have discovered that the prior art shortcomings can, at least in part, be overcome by practice of my invention wherein absorption refrigeration system refrigerant and refrigerant solution flows, temperatures, and pressures are passively controlled in manner which improves system operating efficiencies.